Electrical heater.



A. EIM'ER.

ELECTRICAL HEATER. APPLICATION FILED MAR. 26, 1912. RENEWED MAR. 2a, 1913.

1,070,673, Patented Aug". 19,1913.

' said conductor-carrying member a porous .lated from one another by the intervening 'ing member and the supporting member is UNITED STATES PATENT carton.

AUGUST EIMER, OF NEW YORK, N. Y.

ELECTRICAL HEATER.

Specification of Letters Patent. Patented Aug. 19,1913;

Application filed March 26, 1912, Serial No.-686,238. Renewed March 26, 1913. Serial No. 757,050.

To all whom it may concern:

Be it known that 1, AUGUST Emma, a citizen of the United States, and resident of the borough .of Manhattan, in the city, county, and State of New York, have invented certain new and useful Improvements in Electrical Heaters, of which the following is a specification.

My invention relates to electric heating devices, and particularly to that type in which currents of air are heated by contact with electrically heated resistance conductors or by contact with electrical insulating materials upon which the same are sup ported.

It has for its object to provide a conductor-carrying member of suitable construction and material to obviate short circuiting and contamination of the'heating coil, but to secure at the same timethe maximum of heating effect. To this end I use for the material such as aluminum or magnesium oxid which will withstand expansion and contraction without fracturing; and l mold or construct it in such a manner that there will be upon one or both or all of its surfaces a continuous groove or convolution, said groove having continuous overhanging edges forming non-closing retaining means for the resistance conductors. thus preventing extrusion and short circuiting of the conductor. For example if a resistance wire conductor is intended to be coiled spirally upon or inside a tubular or sectional conductor supporting member, I mold or construct the outer or inner surface thereof so that it forms a groove which is approximately of horse-shoe shape in cross-section and winds helically upon the surface like the thread of a screw or nut. WVhen the resistance member is laid or wound in this groove the various turns of said memberare retained in place and are permanently insuthread of non conducting material. The area of contact. moreover, between the heat greatly increased, with a corresponding in- 1 crease of the quantity of heat conducted I from the heating member to the tube; and since it is intended that the currents of air to be heated shall pass over one or both surfaces of the tubular member, the maximum heating etl'ect is therefore secured by my improved construction. Obviously the tubular supporting member may be provided with coil-receiving grooves and conductors therein upon both its surfaces. It will of course also be understood that a plurality of coil-carrying members of various and appropriate dimensions may be placed or nestedone within another, and that the air currents may be passed between the heating units. In this instance, or in others if desired, the air currents will be heated by contact with the resistance conductor, as Well as with the conductor supporting member. It will also be understood that the heating conductor may be impressed into any suitable continuous convolution upon the surface of 121.) plane or other shaped coil-carrying mem- It is essential for the practical operative employment of my improved electrical heating devices that the material forming the support for the resistance conductors be of refractory material which is a non-conductor of electricity and will withstand expansion and contraction without fracturing.

Examples of such material used by me are aluminum oxid,"magnesium oxid and other fused or unfused members of the groups of rare or common earths whose expansion and contraction is relatively small and unattended with deteriorating effects. The refractory earths I prefer, when used as oxids, or with oxids predominating in their composition, have a porous character, by which I mean that their structure is naturally penetrable by air, and isthus suited to the passage of air heated by .the resistance conductors. Thus, when a conductor is retained interiorly of its support, currents of air passing over said'conductor and heated thereby, may penetrate said support and be ditfused and radiated therefrom. At the same time I do not limit myself to the employment of the aforesaid permeable material for the supports, as they may be of non-porous heat conducting material.

In the drawing accompanying this application, Figure 1 is a vertical section of a portion of the tubular heating member, with an external horse-shoe, helical groove in which is sunk a resistance wire; Fig. 2 is a corresponding view of a heating member having both internal and external grooves containing resistance Wires; Fig. 3 shows a corresponding heating member with an interiorly contained heating member of smaller diameter; Fig. 4 shows a heating member contained in a perforated she l or. casin Fig. 5 shows a-vertical section of a portion of a heating member .With vertical grooves therein containing spiral conductors; Fig. 6 is a. similar view showing two heaters in nested relation; and Fig. 7 is a top plan view of Fig. 6.

The heating member of Fig. 1 as a, has the external, horse-shoe shaped helical groove'b, in which are sunk resistance wires, as c. The heating member is shown as a tube, which may, of course, be of suitable length and of n0n-conducting material capable of radiating heat imparted by the action of electricity as conveyed by the resistance conductor sunk in'its groove. Similarly, the heating member a, shown in Fig. 2, has the external, horse-shoe shaped helical groove Z) containing the resistance wire, as (a; and also an internal, horse-shoe shaped helical groove Z), containing a resistance wire, as c. i

In the example of Fig. 3, an additional heating tube, as (Z, of smaller diameter, is placed Within a tube a, said tube cl having a corresponding helical horse-shoeshaped groove and a resistance conductor sunk therein. The space 6 between tubes a, d is for the passage of air, which becomes heated in such passage, thus increasing the capacity of the device as a heat distributer. Fig. 4 shows a tubular heating member, as a, partially or wholly incased in walls or a shell. as a which is of a foraminous character, as by having the perforations a for the purpose of admitting air to said heater member and conducting the heated air outwardly, thus serving as a radiator.

It is quite unnecessary to illustrate all the forms in which the heater member may be made, and it is sufiicient to state that said members must have grooves to contain continuous sunken resistance conductors, with means for the passage of air thereover to be efiiciently heated and radiated, and said grooves must be provided with overhanging, opposed, separated edges preventing the resistance conductors leaving the grooves, when expanded by heat. In practice a number of said heating units have resistance con duetors which are arranged either in series or multiples, as desired, and said heating units are supported and contained in any suitable manner to serve as heaters or radiators. I

In the modification shown in Figs. 5, 6 and 7 vertical grooves are shown in the inner and outer surfaces of tubular member g, said grooves being stepped, or occurring, on the opposite surfaces of said member, in separate radial planes. Said grooves are substantially of horse-shoe shape in, crossgether tained conductors. The conductors within said grooves may be in hollow tubular or spiral form, permitting the passage of air therethrough, and said conductors are of less sectional area than the grooves for the pasage of air between them and the groove surfaces.

In Figs. 6 and 7 it is shown that members 9 may be snugly nested one within. another, as onaccount of the grooves aforesaid it is not necessary to provide additional spaces between said members for the passage of air. Said conductors obviously may be either in series or multiple electrical arrangement. The resistance conductors employed by me may be either solid or tubular. The provision of a number of air channels and conductors loosely retained therein in the refractory supporting members described permits the passage therethrough and heating of a profusion of air. Hence large quantities of heated air are emitted from my improved heater and disseminated in the surrounding atmosphere.

I claim:

1. An electrical heating device comprising an electrical resistance conductor and a heat diffusing support therefor retaining said conductor in exposed, non-extruding rela tion, said support composed of refractory material which is a non-conductor of elec-' tricity and is of a character to resist fracturing when expanding and-contracting.

2. An electrical heating device comprising an electrical resistance conductor and a heat diifusing support therefor retaining said conductor in exposed, .non-extrudingrelation, said support composed of'porous refractory material which is a non-conductor of electricity and is of a character to resist fracturing when expanding and contracting.

3. An electrical heating device comprising an electrical resistance conductor and a heat diffusing support therefor composed of a refractory earth, in which 'the oxid predominates, the'material' of said support being of permeable character permitting the passage of heated air.

4. In an electrical heating device, a support composed of refractory material of a character to resist fracturing when expanding and contracting, said support having sunken grooves substantially horseshoe shaped in cross section; and non-extruding conductors loosely retained in said grooves.

5. In an electrical heating device, a number of tubular supports composed of refractory material of a character to resist frac turing when expanding and contracting, said supports being snugly nested one within another, and said supports each having siinken outer and inner surface grooves substantially horse-shoe shaped in cross section, towith non-extruding conductors loosely retained in said grooves.

6. An electrical heater consisting of a support of refractory material having a plurality of channels therethrough, and resistance conductors loosely contained Within said channels, ample space being provided between said conductors and channel Walls for the passage of currents of air.

7. An electrical heater consisting of a sup port of refractory material having a plurality of channels therethrough, and tubular resistance conductors loosely contained within said channels, the arrangement being such that profuse quantities of "air may pass through said conductors and between them and the channel surfaces.

Signed. at the borough of Manhattan in the city county and State of New Yorl Copies of this patent may be obtained for five cents each, by addressing the commissioner of Patents, Washington, D. G. 

